Alkylanilinemonosulphonic acids and their manufacture



Patented May 24, 1938 UNITED STATES PATENT OFFICE ALKYLANILINEMONOSULPHONIO ACIDS AND THEIR MANUFACTURE No Drawing. Application January 14, 1937, Se-

rial No. 120,632. 1936 Claims.

This invention relates to new alkylanilinemonosulphonic acids and their manufacture.

In these new alkylanilinemonosulphonic acids, the alkyl group has 6-18 carbon atoms, and is 5 directly attached to the benzene nucleus, and there may be other substituents directly attached to the benzene nucleus, e. g. bromo, chloro, methyl and hydroxy substituents.

These new alkylanilinemonosulphonic acids are valuable dyestuff intermediates.

According to the process of the invention we make the new alkylanilinemonosulphonic acids by treating alkylanilines, in which the alkyl group has 6-18 carbon atoms, and is directly attached to the benzene nucleus and in which there may be other substituents directly attached to the benzene nucleus, e. g. bromo, chloro, methyl and hydroxy substituents, with a sulphonating acid. Two suitable sulphonating acids are fuming sulphuric acid and chlorosulphonic acid.

The alkylanilines which are used as starting materials in the process of our invention may be made from the corresponding anilines or N-alkylanilines by heating them, in the presence of a halide of zinc or cobalt, with saturated primary aliphatic alcohols having 6-18 carbon atoms. In this process the anilines may be wholly or partly replaced by their hydrochlorides or hydrobromides, and the N-alkylanilines may be wholly or partly replaced by their hydrochlorides or hydrobromides, or partly replaced by the hydrochlorides or hydrobromides of the parent anilines. Examples of the alcohols used in making these alkylanilines are hexyl, octyl, decyl, otherwise known as decanol, dodecyl, tetradecyl,

hexadecyl, and octadecyl alcohol. Hexadecyl alcohol is the main or sole component of the alcohols obtained by the saponification of spermaceti: if this is obtained by the saponification of spermaceti its purity may depend upon the purity of the spermaceti. Dodecyl and tetradecyl, otherwise known as myristyl alcohol, are obtained by the reduction of the mixed fatty acids obtained from coconut oil and palm oil. Other alcohols are likewise obtainable by reduction of the fatty acids of natural fats and oils. (See, for instance, Bouveault and Blane, Bull. Soc. Chem. Series 3, vol. 3, pages 6'74 et seq. and 1210 et seq.) The alcohols include mixed alcohols, for instance technical lorol which consists of the mixed alcohols from coconut oil fatty acids. The alkylanilines include those specifically described in the above-mentioned specification, although these may not always be pure compounds or single chemical compounds.

In Great Britain January 17,

One object of our invention is the provision of new alkylanilinemonosulphonic acids, the alkyl group of which has 6-18 carbon atoms, and is directly attached to the benzene nucleus, and

in which there may be other substituents directly I attached to the benzene nucleus, e. g. bromo, chloro, methyl and hydroxy substituents.

Another object of our invention is the provision of valuable dyestuif intermediates.

A still further object of our invention is the provision of a process for the manufacture of the said new alkylanilinemonosulphonic acids, which comprises treating alkylanilines in which the alkyl group has 6-18 carbon atoms and is directly attached to the benzene nucleus and in which there may be other substituents directly attached to the benzene nucleus, e. g. bromo, chloro, methyl and hydroxy substituents, with a sulphonating acid. Further objects of our invention will appear hereinafter.

The following examples, in which parts are by weight illustrate but do not limit the invention.

Example 1.--20 parts of p-dodecylaniline are dissolved in 150 parts of sulphuric acid at 10-15 C. 70 parts of fuming sulphuric acid (20%free S03) are gradually added, and the mixture is stirred for half an hour at 10-15 0., when it is poured into a mixture of ice and water. The precipitate is filtered, washed with water and dried.

The sulphonic acid is a white powder, slightly soluble in water, but readily soluble in water containing a little sodium hydroxide, sodium carbonate or ammonia. Its dilute solutions froth on shaking, and its concentrated solutions form gels on standing.

On treating with bromine (see Abderhalden, Handbuch der Biologischen Arbeitsmethoden, 1933, vol. 2, 2517) the acid forms a dibromosulphonic acid, showing that the sulphonic acid group has entered in the meta position to the amino group, i. e. that the acid is 4-dodecylaniline-3-sulphonic acid.

p-Dodecyl-o-toluidine is sulphonated similarly, the resulting sulphonic acid resembling the l-dodecylaniline-B-sulphonic acid described above.

Example 2.52 parts of p-dodecylaniline are dissolved in parts of tetrachloroethane and a solution of 23.3 parts of chlorosulphonic acid in 25-30 parts of tetrachloroethane added in 20 minutes. The temperature rises during the addition, and at about 80 C., hydrochloric acid is evolved. When all the chlorosulphonic acid is in, the temperature is raised to C., in one hour, during which time hydrochloric acid is rapidly evolved, and then to 140 C. in 10 minutes, after which, evolution of hydrochloric acid ceases. The mixture is cooled, poured into 500-600 parts of water, neutralized with ammonia, the tetrachloroethane separated, and the clear alkaline aqueous solution is acidified with hydrochloric acid. The precipitate is filtered, washed with water, and dried.

The product is a colourless microcrystalline powder, almost insoluble in water, and only sparingly soluble as its sodium salt.

When treated with excess of bromine, the sulphonic acid forms a dibromo derivative, while the sulphonic acid group is split off as sulphuric acid, showing that it occupied an ortho position to the amino group, i. e. that the sulphonic acid is 4-dodecylaniline-2-sulphonic acid.

p-Dodecyl-o-toluidine is sulphonated similarly and the resulting sulphonic acid has similar properties to the 4-dodecylaniline-2-sulphonic acid just described.

Example 3.5 parts of p-decylaniline are dissolved in 30 parts of tetrachloroethane and treated with 2.5 parts of chlorosulphonic acid as described in Example 2. After heating to 140 C., the mixture is cooled, poured into 100 parts of water and the solution boiled. The solution is neutralized with ammonia, evaporated to dryness, and the ammonium-4-decylaniline-2-sulphonate extracted with alcohol. The ammonium salt crystallizes in shining leaflets. Both the ammonium and sodium salts are fairly readily soluble in water.

Example 4.p-Tetradecylaniline is treated with chlorosulphonic acid as described in Example 2, 55 parts of p-tetradecylaniline being used instead of 52 parts of p-dodecylaniline.

4-tetradecylaniline-2-sulphonic acid is obtained as a colourless solid, sparingly soluble in water, and its ammonium and sodium salts are moderately and sparingly soluble respectively.

Example 5 .-22 parts of p-hexadecylaniline are dissolved in 150 parts of 100% sulphuric acid at 15 C. 70 parts of fuming sulphuric acid (20% free S03) are gradually added, and the mixture stirred for an hour at 15 0., when it is poured into a mixture of ice and water. The 4-hexadecylaniline-3-sulphonic acid is filtered, washed with water and dried. It is sparingly soluble in water.

E a: a m p l e 6.-p-Aminohexadecylbenzene is treated with chlorosulphonic acid in tetrachloroethane as described for p-dodecylaniline in Example 2.

4-hexadecylaniline-2-sulphonic tained.

As many apparently widely different embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that we do not limit ourselves to the specific embodiments thereof except as defined in the appended claims.

acid is ob- We claim:

1. Alkylaniline-sulphonic acid in which the alkyl group is a saturated aliphatic radical having 6 to 18 carbon atoms and is directly attached to the benzene ring, in which the benzene ring is substituted by sulphonic acid in one of the positions meta and ortho to the amino group, and a free position of the benzene ring is substituted by one of the group consisting of hydrogen, methyl, chloro, bromo and hydroxy.

2. Dodecylanilinesulphonic acid in which the benzene ring is substituted by sulphonic acid in one of the positions meta and ortho to the amino group, and a free position of the benzene ring is substituted by one of the group consisting of hydrogen, methyl, chloro, bromo and hydroxy.

3. 4-dodecylaniline-3-sulphonic acid.

4. 4-dodecylaniline-2-su1phonic acid.

5. The mono-sulphonic acid of p-dodecyl-otoluidine in which the benzene ring is substituted by the sulphonic acid group in one of the positions ortho and meta to the amino group.

6. The process which comprises interacting an alkylaniline compound in which the alkyl group is a saturated aliphatic radical having 6 to 18 carbon atoms directly attached to the benzene nucleus, in a non-aqueous reaction medium with a sulphonating acid until an alkylaniline-monosulphonic acid is formed.

7. The process which comprises dissolving an alkylaniline compound in which the alkyl group is a saturated aliphatic radical having 6 to 18 carbon atoms directly attached to the benzene nucleus in 100% sulphonic acid, adding fuming sulphuric acid and interacting therewith at about 10 to about C. until an alkylaniline-monosulphonic acid is formed.

8. The process which comprises dissolving an alkylaniline compound in which the alkyl group is a saturated aliphatic radical having 6 to 18 carbon atoms directly attached to the benzene nucleus in tetrachlorethane, adding chlorosulphonic acid and interacting therewith at about 80 to about 140 C. until an alkylaniline-monosulphonic acid is formed.

9. The process which comprises adding about 70 parts of fuming sulphuric acid to a sulphuric acid solution containing about 20 parts of dodecylaniline, and interacting at temperatures of about 10 to about 15 C. until dodccylanilinemono-sulphonic acid is formed.

10. The process which comprises adding about 2 parts of dodecylaniline dissolved in tetrachlorethane to a tetrachlorethane solution containing about 1 part of chlorosulphonic acid, raising the temperature of the mixture to about 140" C. and heating at said temperature until a dodecylaniline-mono-sulphonic acid is formed.

SAMUEL COFFEY. NORMAN HULTON HADDOCK. 

